In recent years pneumatic seats for use in vehicles have been developed. Pneumatic seats comprise a pedestal that includes one or more air bags, a seat supported by the pedestal and a control valve for controlling the pressure of the air in the air bag(s). Pneumatic seats are particularly desirable in vehicles that are driven for extended periods of time, such as long-haul trucks. Because the air in the bag controls the height of the driver's seat, pneumatic seats can be used to adjust the seat to the size and desires of the driver. Further, truck drivers are constantly subjected to vibration and bouncing, which can lead to medical injuries, such as lumbar pain. The air bag pedestal functions as a shock absorber that absorbs the vibration and bouncing that would be transferred to the seat in the absence of the air bags.
One disadvantage of pneumatic seats has been detected. In an accident that results in a vehicle with pneumatic seats tilting severely or rolling over, it is sometimes difficult to extract occupants from the vehicle because inflated pneumatic seats can pin an occupant against the roof or other areas of the vehicle. While the control valve that is used to control the air in the air bags of pneumatic seats can be used to vent air from pneumatic seats, rescue personnel are often not familiar with pneumatic seat control systems. This has led to a need for a device that automatically releases or vents air from a pneumatic seat in the event the vehicle in which the pneumatic seat is located is severely tilted or rolls over. The invention is directed to fulfilling this need.